Field
The presently disclosed subject matter relates to an ultraviolet ray emitting package having a resin adhesive layer and an ultraviolet ray irradiating apparatus using the same.
Description of the Related Art
Generally, a deep ultraviolet ray emitting package for emitting a deep-ultraviolet ray with a short wavelength of about 210 to 310 nm is used for disinfection, sterilization, purification and so on, while an ultraviolet ray emitting package for emitting an ultraviolet ray with a long wavelength of about 310 nm or more is used for exposure and so on.
In FIG. 14, which illustrates a first prior art ultraviolet ray emitting package (see: US2012/0267671A1 & JP2012-227511A), this package 100 is constructed by a substrate 101 with a recess (cavity) 101a defined by an upper portion 101b of the substrate 101, ultraviolet ray (light) emitting diode (LED) elements 102 provided within the recess 101a of the substrate 101, an ultraviolet ray transmitting window member 103 covering the recess 101a of the substrate 101, and a resin adhesive layer 104 serving as a sealing member provided between the upper portion 101b of the substrate 101 and the ultraviolet ray transmitting window member 103. For example, the resin adhesive layer 104 is made of an Ag paste, an ultraviolet (UV) adhesive, Pb-free low-temperature glass, an acryl adhesive or a ceramic adhesive (see: paragraph 0095 of US2012/0267671A1).
In FIG. 14, ultraviolet rays UL1 generated from the ultraviolet LED elements 102 pass through the ultraviolet ray transmitting window member 103 to the outside. On the other hand, ultraviolet rays UV2 generated from the ultraviolet LED elements 102 are incident to the ultraviolet ray transmitting window member 103 and are reflected within the ultraviolet ray transmitting window member 103 to reach the resin adhesive layer 104. Also, ultraviolet rays UV3 generated from the ultraviolet LED elements 102 directly reach the resin adhesive layer 104.
In the ultraviolet ray emitting package 100 of FIG. 14, the resin adhesive layer 104 is irradiated with the ultraviolet rays UV2 and UV3 from the ultraviolet LED elements 102. In this case, since the traverse face of the resin adhesive layer 104 is much larger than the lateral face thereof, the irradiation amount with the ultraviolet rays UV2 is much larger than that with the ultraviolet rays UV3. When the resin adhesive layer 104 includes organic groups, some of the organic groups would be cut by the irradiation with the ultraviolet rays UV2 and UV3, so that the resin adhesive layer 104 would be chemically-modified causing it to deteriorate. For example, organic groups N—H, C—C, . . . , O—O as indicated by R1 in FIG. 15 would be cut by the irradiation with ultraviolet rays whose wavelength is 310 nm or more. If the ultraviolet rays UV2 and UV3 are deep-ultraviolet rays whose wavelength is about 210 to 310 nm, organic groups H—F, O═O, . . . , O—O as indicated by R2 in FIG. 15 would be cut by the irradiation with such deep-ultraviolet rays. Therefore, when the resin adhesive layer 104 is chemically-modified so as to deteriorate, cracks and changes in color would be generated in the resin adhesive layer 104 to degrade the adhesive ability, thus degrading the reliability of the ultraviolet ray emitting package 100 of FIG. 14.
Also, as illustrated in FIG. 16A, when the ultraviolet ray emitting package 100 is arranged on an outer face of an ultraviolet ray transmitting casing 111 in which processing gas or water to be sterilized flows indicated by an arrow AR, and a reflective plate 112 opposing the ultraviolet ray emitting package 100 is provided on the outer face of the ultraviolet ray transmitting casing 111, ultraviolet rays UV generated from the ultraviolet ray emitting package 100 are reflected by the reflective plate 112, so that some of the ultraviolet rays UV would return to the ultraviolet ray emitting package 100. Additionally, as illustrated in FIGS. 16B and 16C, when an additional ultraviolet ray emitting package 100′, similar to the ultraviolet ray emitting package 100, opposing the ultraviolet ray emitting package 100 is provided on an outer face of the ultraviolet ray transmitting casing 111 without the reflective plate 112 of FIG. 16A, some of ultraviolet rays UV generated from the ultraviolet ray emitting package 100 are incident to the ultraviolet ray emitting package 100′, and simultaneously, some of ultraviolet rays UV′ generated from the ultraviolet ray emitting package 100′ are incident to the ultraviolet ray emitting package 100. Therefore, the resin adhesive layer 104 of each of the ultraviolet ray emitting packages 100 and 100′ is chemically-modified by the radiation with the ultraviolet rays UV′ and UV, respectively, so as to deteriorate, cracks and changes in color are generated in the resin adhesive layer 104 to degrade the adhesive ability, thus degrading the reliability of the ultraviolet ray emitting packages 100 and 100′.
Further, when the ultraviolet ray transmitting window member 103 is adhered by the resin adhesive layer 104 to the upper portion 101b of the substrate 101, the ultraviolet ray transmitting window member 103 would slide along the traverse direction due to a temporary reduction of the viscosity of the resin adhesive layer 104.
In FIG. 17, which illustrates a second prior art ultraviolet ray emitting package (see: JP2015-18873A), this package 200 includes a metal layer 201 provided on the side of the substrate 101, a metal layer 202 provided on the side of the ultraviolet ray transmitting window member 103, and an AuSn (or AgSn) eutectic bonding layer 203 provided between the metal layers 201 and 202, instead of the resin adhesive layer 104 of FIG. 14.
In the ultraviolet ray emitting package 200 of FIG. 17, ultraviolet rays UV2 generated from the ultraviolet LED elements 102 are reflected within the ultraviolet ray transmitting window member 103 to irradiate the metal layer 202, and also, the metal layer 202 is irradiated directly with the ultraviolet rays UV3. Even in this case, the AuSn eutectic bonding layer 203 would not be chemically-modified which would cause it to deteriorate. However, since the AuSn eutectic bonding layer 203 would invite a high manufacturing cost, the ultraviolet ray emitting package 200 of FIG. 17 would be high in manufacturing cost.